* eval.c: Removed bogus comment about acros.

* eval.c:  Removed bogus comment about acros.

(scm_unmemocar):  Use !SCM_CONSP instead of SCM_IMP.
Minimize scope of local variable.  Eliminate dependency on
macro DEBUG_EXTENSIONS.

(s_splicing):  New error message string.

(scm_m_body):  Issue 'bad body' message rather than 'missing
expression' message.

(scm_m_quote):  Eliminate unnecessary copying.

(scm_m_lambda, scm_m_letstar, scm_m_letrec, scm_m_let):  Leave the
checking of the body to scm_m_body.

(scm_m_do):  Move comment to function header.  Rename arg1 to
binding.  Made the code a bit easier to read.

(evalcar):  Removed.

(iqq):  Added a comment.  Changed the depth parameter to
unsigned.  Use size_t for vector lengths.  Make sure vector object
is gc protected as long as its contents are read.  Add some syntax
checks.  Get rid of unnecessary SCM_IMP test.  Clean up the
control structure a bit.

(scm_m_delay):  Added comment about the implementation of
scm_m_delay.

(scm_m_define):  Add comment about guile's currying define
syntax.  Renamed 'proc' to 'name'.  Eliminate dependency on macro
DEBUG_EXTENSIONS.  Simplified code a bit.  Eliminate SICP code.

(scm_m_letrec1):  Removed.  Part of the functionality is taken
over by the new function 'transform_bindings'.

(transform_bindings):  New function.  Takes over some of the
functionality of removed function 'scm_m_letrec1', namely to split
a list of bindings into a reversed list of variables and a list of
initializers.

(scm_m_letrec):  Call 'transform_bindings'.

(scm_m_let):  Minimized scope of local variables.  Renamed 'proc'
to 'temp' and 'arg1' to 'binding'.  Eliminated redundant SCM_NIMP
test.  Use 'transform_bindings'.  Fixed scoping error with named
let (Thanks to Aubrey Jaffer for reporting the bug and to Neil
Jerram for suggesting the fix).  Cleaned up the control structure
a bit.

(scm_m_expand_body):  Use 'transform_bindings'.  Eliminated
unnecessary consing.  Eliminated unnecessary
SCM_DEFER/ALLOW_INTS.

(SCM_CEVAL):  Un-obfuscated some loops.